Ipc Sm 840 Solder Mask Pdf Downloadl
Martial Salleh
Notice IPC Standards and Publications are designed to serve the public interest througheliminating misunderstandings between manufacturers and purchasers, facilitat-ing interchangeability and improvement of products, and assisting the pur-chaser in selecting and obtaining with minimum delay the proper product forhis particular need. Existence of such Standards and Publications shall notin any respect preclude any member or nonmember of IPC from manufacturingor selling products not conforming to such Standards and Publication, norshall the existence of such Standards and Publications preclude their voluntaryuse by those other than IPC members, whether the standard is to be usedeither domestically or internationally.
Recommended Standards and Publications are adopted by IPC without regard towhether their adoption may involve patents on articles, materials, or processes.By such action, IPC does not assume any liability to any patent owner, nordo they assume any obligation whatever to parties adopting the RecommendedStandard or Publication. Users are also wholly responsible for protectingthemselves against all claims of liabilities for patent infringement.
MaterialsBryan, Scott, Zycon CorporationCanarr, Leslie, Rockwell InternationalCasson, Keith, Sheldahl Inc.Chouinard, Daniel, MacDermid Inc.Christyson, Rick, Nordson CorporationChu, Sung Gun, Hercules IncorporatedCouble, Edward, Shipley Co.Crane, Lawrence, MacDermid Inc.Crawford, Timothy, EMPFCulver, Duncan, BellcoreDurso, Frank, MacDermid Inc.Einarsson, Kristine, Ericsson Telecom ABElliott, Donald, Elliott TechnologiesFelty, Joe, Texas Instruments Inc.Finch, Kim, Boeing Defense & Space
MaterialsShubert, Fred, Alpha Metals Inc.Slanina, Joseph, AlliedSignal AerospaceSmith, Lance, W. R. Grace & Co.Sullivan, William, MacDermid Inc.Svensson, Jorgen, Ericsson Telecom ABSwenson, Don, AlliedSignal Inc.Tran, William, Morton Electronic
1.1 Scope This standard has been designed and costructed with the intent of obtaining the maximum informtion about and confidence in the solder mask mateunder evaluation with the minimum of test redundanc(See 6.1)
1.2 Purpose This standard enables a vendor to evaluasolder mask, and express the characteristics it posseswhen tested in a standard board system according totest methods and conditions contained in this documenalso enables a printed board designer, manufacturer, anuser to jointly qualify a production board process using ttest methods and conditions contained in this documbased on end use and environmental reliability requiments. Quality conformance of production boards shallevaluated in accordance with IPC-RB-276.
The materials described herein are intended for useprinted boards in order to provide a solder mask to prevsolder bridging, and/or for the retardation of electromigrtion and other forms of conductive growth, and/or for thphysical protection of the printed board.
This specification does not determine the compatibilitysolder mask materials with post soldering products aprocesses. The determination of this compatibility is tresponsibility of the board fabricator/board user. The tprocedures specified herein may be useful tools to demine this compatibility.
Solder mask materials covered in the standard areintended for use as a substitute for conformal coatings tare applied after assembly to cover components, comnent leads/terminations and solder connections.
1.4 Presentation Dimensions and tolerances areexpressed in metric units, with English units shown ibrackets [ ], and are not necessarily direct conversionsorder to provide usable numbers. Users are cautioned
3.1.7 Wrinkling Ridges, creases, or furrows in soldmask covering a melting metal which form after meltinand resolidification. The melting metal reaches its melttemperature and becomes molten under the solder mcoating during soldering causing the coating to appuneven.
3.3 Qualification/Conformance Three separate groupof testing (see 3.3.1-3.3.3) have been defined to provassurance of material consistency and general qualificaas well as production process qualification and confoance. Although each group of testing is designed forspecifically by the solder mask vendor, printed board fricator or designer, they may be conducted and/or modiby written agreement of all concerned parties. Qualificatto a particular class as defined in 1.3 shall not be extento cover any other class.
3.3.1 Solder Mask Material Property Evaluation andConformance Property evaluation and conformancerequired to be performed by the solder mask vendormay, by appropriate agreement, also be used as an incing material inspection procedure by the printed board fricator or user. The tests the solder mask vendor shallform to determine the properties of each formulatiovariation of solder mask material are listed in TableColumn A. Where applicable, test results are to be reporelative to properties defined in the physical requiremesection of this standard.
3.3.2 Solder Mask/IPC-B-25A Test Board System Quali-fication Test board system qualification provides a soldmask vendor with a method to specify the class to whhis product(s) will qualify when tested with a standaboard per tests listed in Table 1, Column B.
Test results must report the laminate material (glass eppolyimide, etc.) and conductor surface (copper, tin-lenickel/gold, etc.) which was used for this type of qualifiction, as well as designating class.
tion Assessment Production board process qualificatioassessment is the responsibility of the printed board fabcator and/or user to confirm. The production process csen is qualified for the designated class and end use apcation. This testing utilizes test coupons evaluataccording to tests listed in Table 1, Column C. By agrement of the printed board fabricator and user, substitpatterns on production board materials may be usedavoid the destruction of production boards.
Requalification by the fabricator shall be required when tsolder mask, conductor surface (copper, nickel, gold, tlead, etc.), or substrate material (glass epoxy, polyimietc.) is changed from that used for the original qualificatiosamples.
3.4 Materials The solder mask and/or boards to bcoated shall be free from deleterious substances and forlated or prepared to meet the designated requirementthis specification. Paragraphs 3.4.1 through 3.4.10 cogeneral characteristics for all solder mask materials.
3.4.1 Formulation Change The following variations inthe formulation of a solder mask material originally qualfied by a supplier constitutes a material change and shrequire a new name or product designation. The extentthe name change is up to the supplier, but the change inname or designation must be prominently displayed andobvious to the user or end-user. Additionally, qualificatioof the changed solder mask formulation to this specifiction is expected. Qualification results of the original fomula are not to be assumed for the new formula (See 6
3.4.2 Compatibility The solder mask materials shall bsuitable for application and use on printed boards and shbe chemically, physically, environmentally, and electricalcompatible with materials of construction. These materiashall not cause deterioration of materials used in printboard assemblies or components mounted/connecthereon. The material shall not corrode any metal beicovered.
3.4.3 Shelf Life The solder mask coating shall be applieand cured within the shelf life specified by the solder mavendor. Shelf life and storage requirements shall be spefied by the solder mask vendor.
3.4.7 Design Solder mask adhesion to melting metal sufaces (solder coating, tin/lead plating, etc.) can notassured as boards are subjected to temperatures that credistribution of the melting metals. When solder maskrequired over melting metal surfaces, in order to be ablemeet the adhesion requirements of this document,maximum recommended conductor width where the macompletely covers the conductor shall be 1.3 mm [0.0inch].
When conductors of melting metal have a width larger th1.3 mm [0.050 inch], the design of the conductor shall prvide a relief through the metal to the base laminate sustrate. The relief should be at least 6.45 mm2 [0.010 squareinches] in size and located on a grid no greater than 6mm [0.250 inch].
When conductor areas of melting metal are to be luncovered, the design for all class boards shall provide tthe solder mask shall not overlap the melting metal. Solmask-to-land relationship shall meet the registratirequirements stated on the master drawing.
3.4.8 Visual Requirements Solder mask appearancshall be observed visually in all stages of evaluation, quafication, and conformance inspection with the aid of a manifying lens rated between 1.75 and 10X magnificatiounless otherwise specified.
The material shall be uniform in appearance and freeforeign materials, cracks, inclusions, peeling, and rougness that would interfere with the assembly or operationthe printed board. Discoloration of metallic surfaces undthe cured solder mask shall be acceptable.
3.4.10 Dimensional Requirements The cured soldermask shall visually cover all required surfaces. Soldmask applied shall withstand a minimum of 500 VDwhen tested in accordance with TM 2.5.6.1 of IPC-TM-65and shall prevent solder pick-up on circuitry during soldleveling and assembly soldering.
3.5.2 Adhesion The following paragraphs providerequirements for testing adhesion of solder mask to rigidflexible substrates. Only those requirements necessaryevaluate material to a particular application need bimposed.
Note: While it is recognized that solder mask has littladherence to tin/lead after it reflows, the solder mashould have sufficient integrity to remain intact during taptesting to meet the requirements of Table 2. See paragra6.4.
3.5.2.1 Adhesion to Rigid Printed Wiring The adhesionof the cured solder mask to melting (e.g. tin-lead or brigacid tin when exposed above its melting point) or to nonmelting (e.g. copper, nickel, etc.) metals shall be detemined in accordance with TM 2.4.28.1 of IPC-TM-650The maximum percentage of cured solder mask lifted frothe surface of the rigid base material or conductive marial of the checker board pattern prior to and subsequentexposure to solder per 3.7.1 shall be in accordance wTable 2.
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